FR2721394A1 - Hand grenade detonation train located in axial channel within main charge - Google Patents

Abstract

A hand grenade has a main charge (not shown) with an axial channel into which extends a multi-stage detonation train comprising a primary charge (3a-5a) which ignites to force a firing pin in the form of a cylinder (7) part axially and part rotatably towards a secondary charge (4a-4d) which then fires the main charge. An end cap (23) is rotatable to set the grenade selectively from a safety setting to a time fuse setting, an impact setting or several impact-fuse settings wherein the grenade explodes a set time after impact.

Description

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  DEVICE FOR FIREDING A PYROTECHNIC CHARGE, OF THE TYPE

  IGNITER CAP IN PARTICULAR FOR HAND GRENADE HAVING THREE MODES

OPERATING.

  The technical sector of the present invention is that of firing devices for a pyrotechnic charge of the igniter plug type, in particular for hand grenade, comprising a pyrotechnic chain initiated in a conventional manner by a striker controlled by the movement of an associated spoon. to a pin. This firing device must integrate the requirements of safety, reliability and low cost price. In particular, the security of storage and transport must be ensured by

  interruption of the pyrotechnic chain.

  This device must also allow the operator to select one of the three operating modes of the following pyrotechnic charge: fusing or percussive mode, or else

hard-hitting mode.

  It is necessary that all the constituent elements can be part of an automated manufacturing process. Their assembly must be designed for a

complete robotization.

  In this technical field, several achievements have been

proposed.

  Patent FR 2,517,048 describes an igniter plug for a hand grenade having three operating modes and a storage and operating safety by interrupting the pyrotechnic chain and blocking the strikers. This plug has two pyrotechnic chains having a common part, one being associated with a first striker specific to fusing operation and the other chain cooperating with a second striker for percussive operation. The selection of the selected operation of the grenade is carried out starting from an external ring provided with a lug on which abuts a plate animated by a movement with rotation of timer. This plate also conditions the alignment of the pyrotechnic train which is obtained after removal of the pin and after a delay

determined by the timer.

  This igniter plug has several drawbacks.

  In particular, it has two non-aligned main strikers

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  between them cooperating with two pyrotechnic chains, which

  leads to complexities of manufacturing and operation.

  Another drawback lies in the association of the alignment of the pyrotechnic train and the arming of the operating modes with a timer, which can harm the safety and the functional reliability of such an igniter plug. A fire, a kinetic impact, or a near explosion, can cause the accidental tearing of the pin followed by the rotation of the plate, causing a pyrotechnic alignment

irreversible chain.

  In addition, the percussion-fusing function corresponds to the self-destruction of the grenade in the event of absence of percussion, and not to a fusing function triggered by the function

impactful.

  Also known is the patent FR 2,458,790 describing a multipurpose igniter plug with launch safety. This plug, very close to that described in the previous patent, has four operating possibilities and includes two independent non-aligned main strikers each corresponding to different operating modes, a selector made up of two rotating discs controlled by a clockwork movement, these participating in storage and launch security. It also includes an impact detector associated with one of the strikers which takes an armed position directly after ejection of the spoon, requiring the

  presence of launch security.

  Here we find most of the drawbacks mentioned above. In particular, the use of a clockwork mechanism, which may have faults, to control the alignment of the pyrotechnic chain and also ensure the safety of the shot. Regarding the percussive-fusing mode, the fusing function

  is not triggered by the percussive function.

  We also know the patent FR 2,682,471 which describes a storage security by interruption of the pyrotechnic chain for an igniter plug. This interruption is achieved by a pivoting element having a radial orifice, placed between the delay module and the priming composition. The rotation of this element, caused indirectly by the ejection of the

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  spoon, automatically causes the final alignment of the

  pyrotechnic chain, especially in an aggressive environment.

  Patent FR 2,465,189 also shows an igniter plug for grenade comprising an interruption of the pyrotechnic chain by a rotary member controlled by a delay mechanism by escapement of glass balls, allowing a final alignment of the chain after a predetermined time. after

priming the chain.

  The principle of operation of the pyrotechnic chain interruptions described in these two patents as well as in the patents mentioned above, has the major drawback of causing automatic and irreversible alignment of the

  chain, in storage in an aggressive environment.

  In addition, during the possible failure of a single essential locking element, which can intervene by accident without human presence (fire, explosion, impacts), inevitably

  the firing procedure is started.

  The object of the present invention is to remedy the drawbacks recalled above, by proposing a device for igniting a pyrotechnic charge, of the igniter plug type applicable in particular, but not exclusively, to hand grenades, having increased safety. during storage, transport and firing, high functional reliability, low manufacturing and assembly costs and perfectly suited to industrial mass production. Another object of the invention is to ensure the safety of storage and transport in initiated full shots, by

  interruption of the pyrotechnic chain.

  The invention also aims to provide an igniter plug directly adaptable to different types of pyrotechnic devices and more particularly to several models of hand grenades (offensive, defensive, tear smoke or exercise), while retaining conventional means of bet

  implemented, such as the spoon and pin combination.

  Another object is to allow the user to select from the igniter plug, one of the following three operating modes of the pyrotechnic charge: mode

  fusant, or percussive, or percussive-fusant.

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  To do this, the invention relates to a device for igniting a pyrotechnic charge, of the igniter plug type, in particular for a hand grenade, comprising, housed in an axial bore made in the body of the plug, a pyrotechnic chain in two upstream and downstream parts, the downstream part being fired by an axial striker placed between the two parts of the chain and associated with control means cooperating with a locking means. This device comprises mechanical means for controlling the striker, which are interposed between the upstream part of the chain and the latter to drive the striker in an axial and rotary movement around its axis, under the pressure of the gases generated by

the initiation of the upstream part.

  Preferably, the mechanical means for controlling the striker cooperate with a guide member engaged in a

  ramp at the bore of the plug body.

  Preferably, the control means of the hollow cylindrical striker are constituted by a spring and a piston sliding axially relative to the central bore, housed in a fixed cylindrical internal body containing the upstream part of the pyrotechnic chain, this body being partially fitted

in the striker.

  The means for locking the striker with the internal body may consist of a ball protruding into a housing of the body and allowing the striker to pass from an initial safety position, where the piston keeps the ball engaged in a circular groove internal of the striker, in an armed position, after axial displacement of the piston, in which the ball positioned opposite an external circular groove of the piston

  comes out of the internal circular groove of the striker and releases it.

  Preferably, the guide member consists of a ball projecting into the central bore engaged in the ramp produced on the external wall of the striker, this ramp comprising a longitudinal part extended by a helical part, so as to produce a first axial movement of the striker followed by a second movement, both rotary and

axial of the same striker.

  The device may include a module for neutralizing the striker, disposed between the latter and the downstream part of the

pyrotechnic chain.

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  This cylindrical neutralization module can have three series of lights of different lengths distributed over the periphery of the module, for housing at least

minus a lug of the striker.

  The striker can include three external pins distributed at 120 on its periphery and placed opposite one of the three series of lights also distributed on the module to achieve either neutralization of storage and transport in the striker safety position, or a functional neutralization in its armed position, i.e. firing

of the downstream part of the chain.

  Preferably, the device comprises a self-destruction module comprising a gas-generating composition contained in the piston and initiated by the upstream part of the chain, an exhaust vent made in the piston and placed, after displacement of the piston, opposite of an axial volute fixed to the striker, to cause under the effect of the control means a rotary and axial movement of the latter followed by the setting

  fire in the downstream part of the chain.

  The gas-generating composition contained in the piston may consist of a delay composition associated with a

reinforcing composition.

  According to a preferred embodiment, the firing device according to the invention, comprising an axial element for interrupting the pyrotechnic chain placed in the downstream part of the chain housed in a cylindrical case, comprises mechanical drive means of the axial interrupting element actuated by the only rotation of the head of the igniter plug, thus allowing alignment and

  manual chain misalignment.

  This interrupting element may consist of a cylinder pierced with an axial orifice, fixed to an alignment barrel driven in rotation by the mechanical means of a position

  radial to an axial position of the cylinder and vice versa.

  The mechanical means for driving the barrel in rotation may consist of a cylindrical internal part movable in rotation partially housed in the case and connected by its lower end to the barrel, its upper end being

  driven by the rotation of the body and the head of the cap.

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  According to a first embodiment, the barrel is provided with a tenon engaged in a helical groove made in

  the cylindrical case, ensuring a 90 rotation of the cylinder.

  According to a second embodiment, the barrel has teeth engaged in a rack of the case to ensure

a 90 rotation of the cylinder.

  Preferably, the downstream part of the pyrotechnic chain successively comprises a percussion primer, a charge of lead azide, a hexogen priming relay, the element

  interruption cylinder then a main relay in hexogen.

  According to a preferred embodiment, the interrupting cylinder also contains a relay charge

  intermediate in secondary explosive of the hexogenic type.

  The device for igniting a pyrotechnic charge according to the invention applied to a three-function igniter plug

  allowing a fusing, impactful, or impactful-

  load fuse, of the type comprising a selector of operating modes, an impact detector module and a timer module, is preferably provided with a selector constituted by the cylindrical external wall of the plug head, movable in rotation around the cylindrical body of the plug pierced by

the central bore.

  The timer module secured to the selector may include a mechanical oscillator regulating the rotation of at least one toothed wheel meshed in at least one axial rack fixed to the external wall of the striker, to produce a

  percussion delay in percussive-fusing mode.

  According to an alternative embodiment, the external wall of the striker comprises four parallel racks of different lengths each corresponding to percussion delays of one second, seven tenths, four tenths and one tenth of a second. Preferably, an omnidirectional impact detector module with adjustable sensitivity will be used, for the striking mode and the striking-fusing mode, housed in an axial bore of the cylindrical body of the plug, comprising a master cylinder associated with a first spring, a counter-cylinder associated with a second spring, a transverse detection ball interposed between the master cylinder and the counter-cylinder, two locking and unlocking balls of the module controlled by the

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  axial movement of the striker and another locking ball and functional unlocking of the module preventing

  or authorizing its operation by the action of the selector.

  Preferably, the transverse detection ball of the impact detector module is made of a dense material of the tungsten type. Preferably, the selector comprises in the safety position means preventing the extraction of a pin locking a spoon and an upstream striker controlling the firing of the

upstream part of the chain.

  According to a preferred operating mode, the rotary selector occupies an initial safety position and takes, by successive rotations of 90, at least three different positions, each corresponding to one of the operating modes: - in the safety position, the pin is locked, the pyrotechnic train is interrupted by the element maintained in the radial position, the striker, the three pins of which face the three short safety lights, is locked by the ball engaged in the internal circular groove of the striker, the gear wheel of the timer module is located away from the racks of the striker, and the impact detector module is locked by the two balls blocking respectively the master cylinder and the counter-cylinder under the action of the striker in the initial position, more the functional locking ball held by the selector also blocks the master cylinder, - a first rotation of 90 of the sel ctor, corresponding to the fusing operation of the load, causing successively, the unlocking of the pin authorizing its extraction, the alignment of the pyrotechnic train by rotation of the interrupting element, and the relative rotation of the neutralization module relative to the striker by placing the three longer lights of the module opposite the three lugs of the striker corresponding to the functional neutralization position of the striker, the timer and impact detector modules remaining inactive, - a second rotation of 90 of the selector, corresponding to the operation impactful, further causing the release of the functional locking ball of the detector module

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  impact, the latter being housed in an internal circular groove of the selector to make this module active, - a third rotation of 90 of the selector, corresponding to the percussive-fusing operation, causing moreover, the alignment of the toothed wheel of the timer module with the first rack of the striker corresponding to a percussion delay of one second, the impact detector module remaining active. According to a variant of operation, the selector being in the striking-fusing position, three successive additional rotations in the same direction of the selector causing the alignment of the toothed wheel of the timer module with respectively, the second rack of the striker corresponding to a percussion delay by seven tenths, the third rack of the striker corresponding to a percussion delay of four tenths and the fourth rack of the striker corresponding to a percussion delay of one tenth

second.

  According to another operating variant, in the striking and striking-fusing position of the selector and in the absence of operation of the impact detector module, the self-destruction module associated with the striker control means cause the part to ignite. downstream of the chain followed

of the explosion of the object.

  An advantage of an igniter plug according to the invention lies in the compactness of its structure and the modularity of its constituent elements, notably simplifying the firing conditions and the manufacturing steps encountered during a

largely automated production.

  This igniter plug has several operating modes

  offers optimized shooting and storage security.

  In particular, the interrupting element of the pyrotechnic chain judiciously placed within the downstream part thereof, is independent of the environment for better efficiency in the event of accidental initiation of the upstream part of the chain, at during transport or storage of the associated cork

to the pyrotechnic charge.

  This interruption element can be moved only by the voluntary intervention of the operator. As a result, the purely manual alignment and misalignment of the train

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  pyrotechnic, cannot result from the conjunction of elements

aggressive exteriors.

  This has the advantage of allowing the safe storage of the igniter plug mounted on a hand grenade, for example in a complete hit, which is not the case.

  currently with existing igniter plugs.

  Another advantage lies in the positioning at the center of the main load of the main initiation relay, ensuring

  thus an isotropic detonation of the pyrotechnic charge.

  Other characteristics and advantages of the invention

  will appear in the detailed, non-limiting description, of a

  embodiment of the invention.

  This description will be made with reference to the drawings

  annexed among which: - Figure 1 shows an axial sectional view of a three-function igniter plug according to the invention, in the safety position, - Figure 2 shows a view on an enlarged scale, along AA of Figure 1 of the neutralization module associated with the striker in the storage or transport position, - FIG. 2A represents a view according to FIG. 1 of the neutralization module alone, - FIG. 3 represents a side view of the striker, showing on an enlarged scale, the relative path of the guide member in the longitudinal and helical ramp participating in the movement of the striker, - Figure 4 shows a side view of the striker associated with the timer module, - Figure 5 shows an axial sectional view of a grenade offensive-defensive hand equipped with an igniter plug according to the invention, showing more particularly the downstream part of the pyrotechnic chain with its interrupting element, in the position of s reté, as well as the locking means of the pin, - Figure 6 shows, on an enlarged scale and according to Figure 5, the interrupting element of the pyrotechnic train, according to a first embodiment, - Figure 7 shows a view identical to FIG. 6, of a second embodiment of this element,

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  - Figures 8 and 8A show a top view of the selector with indication of the different operating modes, showing the means for locking the pin in the safety position, - Figures 9, 9A, 9B and 9C are views in radial section according to BB of FIG. 1 respectively, at the level of the fixed case, the selector, the body of the plug and the upper part of the internal part containing the neutralization module, - FIGS. 10, 10A, 10B, 10C and 10D represent a partial schematic view according to FIG. 1, showing the different positions of certain moving parts respectively in position, of safety, of alignment of the pyrotechnic train, fusing, striking and percussion-fusing, - FIGS. 11, 11A and 11B represent a partial view according to FIG. 1, illustrating the movements of the piston and of the striker to the armed position of the latter, in percussion-fusing operating mode, - FIG. 12 represents a view according to the Figures 11 to 11B, after firing by the operation of the impact detector module, - Figure 13 shows a view according to Figures 11 to 1iB, after firing by the operation of the self-destruction module. Referring to Figures 1 to 3 we see a three-function igniter plug of substantially cylindrical shape comprising at its lower part a case 26 provided with an external thread to adapt the plug to a hand grenade for example, not shown. On this lower part, the main part of the plug surmounted in rotation is surmounted by the head of the plug comprising conventional means for initiating a pyrotechnic chain such as a pin 34 and a spoon 22 controlling an upstream striker 29. The present invention is not

  not on these known conventional means.

  The main part of the plug comprises three hollow cylindrical parts 23, 24 and 25 coaxial superimposed and movable in rotation with respect to each other. It has two axial bores 2 and 37. Central bore 2 is

  extends into the fixed case 26 screwed into the grenade.

  In this central bore 2 formed in the cylindrical part 24 are mounted from top to bottom: there 2721394 - an internal body 1, fixed to the cylindrical part 24, having a solid upper part provided with a central cylindrical housing containing an upstream part 3 a pyrotechnic chain in two parts, and a hollow lower part, - a primer 3a, a pyrotechnic delay 3b and a reinforcing charge 3c generating gas, constituting the upstream part 3 of the chain, - a hollow cylindrical piston 5 sliding axially which has an external circular groove 5d and an axial gas exhaust vent 5c at its lower part, the piston being held in the high position by a spring 6 and these two elements being housed in the hollow lower part of the body 1, - a gas-generating composition comprising a delay composition 5a associated with a reinforcing composition 5b, contained in the piston 5, - a hollow cylindrical striker 7 having in axial section the shape of a U, movable in axial translation and in rotation about its axis with respect to the fixed internal body 1 partially contained in the striker, - a ball 8 for locking and unlocking the striker with the body 1, projecting into a housing in the lower part of this body; in the high position of the piston, the ball bears on the one hand on the external wall of the latter and is engaged in an internal circular groove 7f of the striker on the other hand, - a neutralization module 20 (FIG. 2) of the striker disposed under the latter and secured to the cylindrical part 25, consists of a hollow cylinder provided at its periphery with three series of axial lights 20a, 20b and 20c of different lengths distributed at 120; a first series comprising three short lights 20a for neutralizing storage and transport, a second series comprising three longer lights 20b for functional neutralization and a third series comprising three open lights 20c

  allowing the striker to pass freely.

  The lower end of this bore 2 communicates with a coaxial bore of the fixed case 26, containing the downstream part 4 of

the pyrotechnic chain.

  The lower part of the striker 7 comprises three external pins 7e distributed at 120 on its periphery, capable of being housed

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  in the three series of lights 20a, 20b and 20c of the neutralization module. On the internal face of this lower part of the striker 7 is fixed an axial scroll 7d communicating with the exhaust vent 5c of the piston 5 in the low position and causing the striker to rotate under the effect of the gases produced by the combustion of the pyrotechnic composition 5a

and 5b contained in the piston 5.

  This neutralization module also includes an axial lug 21 for neutralization indication, projecting outside the module through a recess 26a of the latter when one of the three lugs 7e of the striker is resting on its part. superior. In the extended position, this lug 21 constitutes a stop preventing the relative rotation of the module 20 and the selector 23 relative to the fixed case 26, and indicating to the operator the neutralization position occupied

by the striker.

  A ramp 7a, 7b (FIG. 3) is hollowed out in the cylindrical external wall of the striker 7. It comprises a longitudinal part 7a extended by a helical part 7b in which is engaged a guide member consisting of a ball 9 movable in rotation in an open housing formed in the body 24 of the plug and projecting into the bore

central 2 of the plug.

  In this Figure 3 is shown in broken lines, the different positions taken by the ball 9 in the longitudinal ramp 7a and helical 7b during the movement of the striker. This ball successively occupies positions 9a, 9b, 9c and 9d after respectively, a first axial movement of the striker, a second rotary and axial movement corresponding to the armed position of the striker, a third movement caused by the action of the self-destruct module , a fourth displacement leading to percussion

  of self-destruction or of the fused operating mode.

  It will be noted that the configuration of the guide member and of the ramp described above is not limiting, and that an alternative embodiment where the ramp would be dug in the

  body 24 of the plug at the bore and the guide member placed on the cylindrical wall of the striker 7 for example, is also covered by the present invention.

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  Four axial racks 7c, 7c2, 7c3 and 7c4 parallel and of different lengths are fixed on a zone of the cylindrical external wall of the striker diametrically opposite to that comprising the ramp described above. In percussive-fusing mode of operation of the charge, as will be described later, these racks provide percussion delays of one second, seven tenths, four tenths and one tenth of

second (Figure 4). A timer module is placed, through a window practiced in the

  body 24 of the plug, in the cylindrical external part 23 forming the head of the plug used to select the different modes of operation of the pyrotechnic device. This timer module, secured to the selector 23 by any known means, is rotated by the latter around the striker, to align with one of the

  four axial racks of the striker in percussive mode-

  fusant. This purely mechanical timer module includes an oscillator 19 regulating the rotation of one or more toothed wheels 18 which can mesh in one of the four racks, according to the duration of the percussion delay chosen by

  the operator from selector 23.

  An omnidirectional impact detector module with adjustable sensitivity is mounted in the second axial bore 37 which may have a diameter equal or not to that of the central bore 2. This second bore 37 is formed in the body 24 of the plug

  short distance from the central bore 2.

  This impact detector module, used in percussive mode and in percussive-fusing mode, comprises: - a master cylinder 10 associated with a first spring 11 bearing on the bottom of the bore 37 on the one hand and on the part lower of the master cylinder, - a counter-cylinder 12 associated with a second spring 13 bearing on the upper end of the bore 37 on the one hand and on the upper part of the counter-cylinder, - a ball 14 in tungsten transverse detection, inserted between the master cylinder and the counter-cylinder, radially movable in an internal housing of the body 24 of the plug and of the selector 23,

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  - Two balls 15 and 16, radially movable in two housings of the part of the body 24 located between the two bores 2 and 37 and each projecting in these two bores, locking in the high position of the striker 7 and unlocking after axial movement of the latter ci respectively, the master cylinder 10 and the counter cylinder 12, - a ball 17, radially movable in a housing of the body 24, ensuring the functional locking of the module under the action of the selector 23 which keeps it engaged in a groove of the master cylinder 10, and the functional unlocking allowing the operation of the module after a rotation of the selector around the body 24 allowing this ball to escape from the groove of the master cylinder to be housed in a

  internal circular groove 23b of the selector.

  In the high position of the striker 7, the locks of these two elements of the module are provided by the striker which keeps each of the balls 15 and 16 engaged in the corresponding groove of the master cylinder and the counter-cylinder. The master cylinder 10 is in contact with the ball 9 and the

  maintains engagement in the ramp 7a, 7b of the striker. This master

  cylinder has two notches 10a allowing, after axial displacement of the latter caused by a longitudinal or transverse impact, the exit of the ball 9 from the ramp

releasing the striker.

  The selector 23 constituted by the cylindrical head of the plug has at its lower part an elastic lock 23a which snaps into a circular notch made in the fixed case 26. On the periphery of the upper part of the selector 23 (FIG. 8A) four main markers are arranged corresponding to the safety positions,

  Fusing, impactful and impactful-fusing operation.

  The operator accesses each of these four marks by successive rotations of 90. In the striking-fusing position, the selector has three secondary references, accessible by successive rotations of 20 for example, corresponding to the different

  percussion delays described above.

  An external element around the upper part of the case 26 has a circular rib 26e (FIGS. 5 and 8) trapping, using the elastic lock 23a of the selector in the safety position, part of a ring 34a connected to the

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  pin 34, to prevent the extraction of the latter

  only when the selector is in the safety position.

  In the fixed cylindrical case 26 screwed into the grenade, is mounted the downstream part 4 of the pyrotechnic chain. This downstream part 4 comprises from top to bottom: a percussion primer 4a, a charge 4b in lead azide, a priming relay 4c in hexogen, a cylinder element 27 for interrupting the chain

  then a main 4d hexogen relay (Figures 5 to 7).

  This element 27 for interrupting or misaligning the pyrotechnic train consists of a cylinder pierced with an axial orifice and preferably containing an intermediate relay charge in secondary explosive of the hexogenic type. It is fixed by any known means to a cylindrical barrel 28 driven in rotation by mechanical means from a radial position to a position

  axial of the element and vice versa.

  These mechanical means, actuated only by manual rotation of the selector 23 constituted by the head of the plug, comprise an internal cylindrical part 25, the lower part 25a of which is housed in the case 26 and the upper part containing the neutralization module is driven by rotation by the

  body 24 of the cap covered by the selector 23.

  According to a first embodiment (FIG. 6), these mechanical means comprise a helical groove 31 made in the case 26 associated with a tenon 30 of the barrel 28 movable in rotation in the lower end 25a of the internal part 25, so to achieve a rotation of 90 of the interrupting element 27 by a joint rotation of 45 of the body 24 and the selector, in the initial safety position. Beyond 45, the upper part of the part 25 is locked with the fixed case 26, in order to keep the alignment of the pyrotechnic train for the three operating modes. The return to the safety position of the selector 23 unlocks the part 25 of the case 26 and causes the pyrotechnic train to be misaligned by returning to

radial position of the element 27.

  According to a second embodiment (Figure 7), the helical groove assembly 31 associated with the stud 30 is replaced by a toothed wheel 32 of the barrel 28 meshed in a circular rack 33 of the case 26 to ensure alignment and misalignment of the pyrotechnic train by rotation of 90 from

the interrupting element 27.

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  The operation of the firing device according to

the invention is as follows.

  The igniter plug being mounted in the safety position on a pyrotechnic device of the hand grenade type for example, the operator chooses one of the three operating modes by rotating the head 23 of the plug around the case by hand.

fixed 26 screwed on the machine.

  In the initial safety position, the pin 34 cannot be removed, the element 27 in the radial position interrupts the pyrotechnic chain, the three lugs 7e, of the striker 7 locked in the high position, are opposite the three short lights 20a, and the timer and impact detector modules are

inactive (Figure 10).

  Provided that the neutralization indication lug 21 has not returned inside the recess 26a, the operator can rotate the selector 23 in one direction only by exerting pressure on the snap-on elastic lock 23a in the circular notch of the fixed case 26, to select the

desired operating mode.

  During the angular displacement from 0 to 45 of the selector 23, the three cylindrical parts 23, 24 and 25 can rotate simultaneously with respect to the fixed case 26, thanks to two cams 23d and 24b, forming part of the respective ends of the parts 23 and 24, provided with two studs 23c and 24a sliding in corresponding grooves 26b and 26c of the case (Figures 9

at 9B).

  At position 45, not indexed, of the selector, the alignment of the pyrotechnic train is achieved (FIG. 10A) by the rotation of 90 of the interrupting element 27 produced by the rotation of the internal part 25, the latter is then locked with the case 26 to keep the alignment of the train during the selection of the operating modes. This locking is achieved by an elastic lug 25b, located at the end of the part 25, sliding in the groove 26d of the case 26, where it

  locks at the end of the groove (Figures 9 and 9C).

  It will be noted that the misalignment of the pyrotechnic train can again be carried out by reverse rotation and return to

safety position.

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  During the angular displacement from 45 to 90, the two cylindrical parts 23 and 24 remain integral and rotate

  simultaneously with respect to the locked internal part 25.

  It will be noted that the striker 7 is linked in rotation with the cylindrical part 24 by the ball 9 engaged in the

ramp 7a, 7b thereof.

  At position 90, corresponding to the fusing operating mode (FIG. 10B), the rotation of the part 24 and therefore of the striker 7 placed the three lugs 7e of the latter facing the three longer lights 20b of functional neutralization, the detector module impact remains blocked by the functional locking ball 17 held in engagement in the groove of the master cylinder 10 by the selector, and the module

  timer remains away from the racks 7c of the striker.

  In this position, the operator can extract the pin 34 by pulling on the ring 34a released by the erasure of the circular groove 26e of the case 26, the cylindrical part 24 being locked with the upper part of the internal part 25 by snap-fastening at the rib 26c and

  of the elastic cam 24b associated with its stud 24a.

  At position 180, corresponding to the percussive operating mode (FIG. 10C), the functional locking ball 17 comes out of the groove of the master cylinder 10 and is housed in the internal circular groove 23b of the selector to activate the

impact detector module.

  In this position, as in the previous position, the timer module remains away from the racks 7c of the striker. The part 24 is locked on the case 26 by a

  lug 24c in the groove 26f of the case.

  During the angular displacement from 180 to 270, the selector 23, associated with the timer module, rotates around the

body 24 of the plug.

  At position 270, corresponding to the percussive-fusing operating mode (FIG. 10D), the toothed wheel 18 of the timer module is aligned with the first rack 7c of the striker corresponding to a percussion delay of one second, and the functional locking ball 17 stay free for

  leave the impact detector module active.

  The other angular positions of the selector which can be, for example, 300, 320 and 340 correspond

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  respectively to the alignment of the toothed wheel 18 with the racks 7c2, 7c3, and 7c4 for percussion delays of seven tenths, four tenths and one tenth of a second. In these last three positions, the impact detector module also remains active. Each of these four positions is

indexed by cam 23c.

  It is described below the operation of the device in percussion-fusant mode mounted on a hand grenade (Figures 11

at llB and 12).

  Differences in operation according to the other two

  modes can easily be deduced from it.

  We place ourselves here in the configuration relating to this particular mode of operation, determined by the position

  corresponding to the selector, described above.

  The operator extracts pin 34 and launches the grenade. The spoon 22 releases the upstream striker 29 which strikes the primer 3a of the upstream part 3 of the pyrotechnic chain (FIG. 11). The

following actions follow one another.

  The combustion of the pyrotechnic delay 3b ignites the reinforcing charge 3c which generates gases causing the displacement

  axial of the piston 5 compressing the spring 6.

  As soon as the external circular groove 5d of the piston 5 arrives opposite the ball 8, the latter releases the striker cylinder 7 which then moves axially under the action of the spring 6

compressed.

  The longitudinal part 7a of the striker ramp slides in front of the ball 9 until it meets the part

  helical 7b of the ramp (Figure 11A).

  The helical shape of this part of the ramp gives the striker cylinder a rotation of a few degrees. At the end of the helical part 7b, the striker

  stops, retained by the ball 9 (Figure 11B).

  It should be noted that the striker 7 forced by the helical part of the ramp to a rotation, allows the three lugs 7e of the striker to move away from the three long lights 20b of functional neutralization of the neutralization module, to position themselves opposite the three through lights 20c, thus authorizing effective arming of the device. This original trick makes it possible both to control the presence of the ball 9 guiding the striker,

19 2721394

  as well as the triggering of percussion, and the integrity of the impact detector module. If one had failed, the striker would have dived into the neutralization lights

functional 20b.

  In its movement, the striker released the two balls 15

  and 16 and thus unlocked the impact detector module.

  A longitudinal impact, producing an axial displacement of the master cylinder 10, ball 14 and counter-cylinder 12, or transverse movement, radially displacing the ball 14, necessarily causes the axial displacement of the master cylinder 10, one of the two indentations 10a allows the ball 9 to exit from the helical part 7b of the ramp causing the release of the

striker (Figure 12).

  In its movement towards the downstream part 4 of the pyrotechnic chain, the striker is delayed by the timer module. Indeed, the rack 7c of the striker (or one of the shorter racks 7c2, 7c3 and 7c4, depending on the selected percussion delay) comes into contact with the toothed wheel 18 which very strongly brakes the striker (Figures 11B

and 12).

  After a delay, depending on the length of the rack, the striker is finally released and will ignite the

  downstream part 4 of the chain by striking the primer 4a.

  If the impact detector module does not release the ball 9 in due time, the self-destruction module contained in the

  piston 5 takes over (figure 13).

* Indeed, the propellant charge 3c activated the delay composition 5a. At the end of combustion, the reinforcing composition 5b generates gases, the flow of which through the

  volute 7d forces the striker to a new rotation.

  The upper end of the helical part 7b of the ramp

  then presents itself to the ball 9 which disappears (FIG. 3).

  This additional rotation of the striker has misaligned the rack 7c with the toothed wheel 18 of the timer module of

  so that the percussion of self-destruction is instantaneous.

  Concerning the operation in striking mode, it is identical to the striking-fusing mode, however the rotation of the selector 23 leaves the racks of the striker to

away from the timer module.

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  Regarding the fuse mode operation, it is similar to the impact-fuse mode, however the rotation of 90 of the selector 23 also leaves the racks of the striker away from the timer module and does not release the functional locking ball 17 of the impact detector module which therefore remains inactive, so that the self-destruction of the grenade

is inevitable.

21 2721394

Claims (20)

  1. - Device for igniting a pyrotechnic charge, of the igniter plug type in particular for a hand grenade, comprising, housed in an axial bore (2) formed in the body (24) of the plug, a pyrotechnic chain in two parts (3,4) upstream and 5 downstream, the downstream part (4) being ignited by an axial striker (7) placed between the two parts of the chain and associated with control means cooperating with a locking means, device characterized in that the mechanical control means (5,6) of the striker are interposed between the upstream part of the chain and the latter, to drive the striker (7) in an axial and rotary movement around its axis, under pressure gases generated by the initiation of the upstream part (3) of the pyrotechnic chain. 2. Device according to claim 1, characterized in that the mechanical control means (5,6) of the striker cooperate with a guide member (9) engaged in a ramp (7a, 7b) at the bore ( 2) of the body (24) of the plug. 3. - Device according to claim 2, characterized in that the control means of the striker (7) hollow cylindrical consist of a spring (6) and a piston (5) sliding axially relative to the central bore (2) , housed in a fixed internal cylindrical body (1) containing the upstream part of the pyrotechnic chain, this body being partially fitted in the striker (7).   4. - Device according to claim 3, characterized in that the locking means of the striker (7) with the internal body (1) consists of a ball (8) projecting into a housing of the body (1) and allowing for the striker to move from an initial safety position, o the piston (5) keeps the ball engaged in an internal circular groove (7f) of the striker, in an armed position, after axial displacement of the piston, in which the ball ( 8) positioned opposite a circular groove (5d) of the piston exits from the circular groove   internal (7f) of the striker and releases it.   5. - Device according to claim 4, characterized in that the guide member consists of a ball (9) making 22 2721394   projection in the central bore (2) engaged in the ramp produced on the external wall of the striker, this ramp comprising a longitudinal part (7a) extended by a helical part (7b), so as to achieve a first axial displacement of the striker followed by a second trip to   both rotary and axial of the same striker.   6. - Device according to claim 5, characterized in that it comprises a neutralization module (20) of the striker (7), disposed between the latter and the downstream part (4) of the pyrotechnic chain.   7. - Device according to claim 6, characterized in that the neutralization module (20) of cylindrical shape has three series of lights (20a, 20b, 20c) of different lengths distributed over the periphery of the module, for the   housing at least one lug (7e) of the striker (7).   8. - Device according to claim 7, characterized in that the striker comprises three external lugs (7th) distributed at 120 on its periphery and placed opposite one of the three series of lights also distributed on the module to produce, either neutralization of storage and transport in the safety position of the striker, either a functional neutralization in the armed position of the striker, or firing of the downstream part (4) of the chain.   9. - Device according to claim 8, characterized in that it comprises a self-destruction module comprising a gas generating composition (5a, 5b) contained in the piston (5) and initiated by the upstream part of the chain, a exhaust vent (5c) formed in the piston and placed, after displacement of the piston, opposite an axial volute (7d) fixed to the striker, to cause under the effect of the control means a rotary and axial movement of this last follow-up of the update   fire in the downstream part (4) of the chain.   10. - Device according to claim 9, characterized in that the gas generating composition contained in the piston (5) consists of a delay composition (5a) associated   to a reinforcing composition (5b).   11. - Device according to any one of claims   above, comprising an axial element for interrupting the pyrotechnic chain placed in the downstream part of the chain housed in a cylindrical case (26) and driven in rotation by 23 2721394   mechanical means, characterized in that the mechanical drive means of the element are actuated by the only rotation of the head (23) of the igniter plug, allowing   thus manual alignment and misalignment of the chain.   12. - Device according to claim 11, characterized in that the interrupting element consists of a cylinder (27) pierced with an axial orifice, fixed to an alignment barrel (28) driven in rotation by the mechanical means of a position   radial to an axial position of the cylinder and vice versa.   13. - Device according to claim 12, characterized in that the mechanical means for driving the barrel in rotation (28) consist of an internal cylindrical part (25) movable in rotation partially housed in the case (26) and connected by its lower end (25a) to the barrel, its upper end being driven by the   rotation of the body (24) and the head (23) of the plug.   14. - Device according to claim 13, characterized in that the barrel is provided with a pin (30) engaged in a helical groove (31) formed in the cylindrical case (26),   ensuring a 90 rotation of the cylinder (27).   15. - Device according to claim 13, characterized in that the barrel (28) comprises teeth (32) engaged in a rack (33) of the case to ensure a rotation of 90 of the cylinder.   16. - Device according to any one of claims   above, characterized in that the downstream part (4) of the pyrotechnic chain successively comprises a percussion primer (4a), a charge (4b) in lead azide, a priming relay (4c) in hexogen, the element cylinder   (27) then a main relay (4d) in hexogen.   17. - Device according to claim 16, characterized in that the interrupting cylinder (27) also contains an intermediate relay charge in secondary explosive of the hexogenic type 18. - Application of the device for igniting a charge   pyrotechnic according to any one of the claims   previous, to a three-function igniter plug allowing fusing, percussive, or percussive-fusing operation of the load, of the type comprising a selector of operating modes, an impact detector module and a module 24 2721394   timer, characterized in that the selector is constituted by the cylindrical external wall (23) of the cap head, movable in rotation around the cylindrical body (24) of the cap drilled through the central bore (2).   19. - Igniter plug according to claim 18, characterized in that the timer module secured to the selector (23) comprises a mechanical oscillator (19) regulating the rotation of at least one toothed wheel (18) meshed in at least one rack axial (7c) fixed on the external wall of the striker (7), to produce a percussion delay in percussive-fusing mode. 20. - Igniter plug according to claim 19, characterized in that the external wall of the striker (7) comprises four racks (7c, 7c2, 7c3, 7c4) parallel with different lengths each corresponding to percussion delays of one second, seven tenths, four tenths and one tenth of a second. 21. - Igniter plug according to claim 20, characterized in that the omnidirectional impact detector module with adjustable sensitivity, used in percussive mode and in percussive-fusing mode, housed in an axial bore (37) of the cylindrical body (24) of the plug, comprises a master cylinder (10) associated with a first spring (11), a counter-cylinder (12) associated with a second spring (13), a detection ball (14)   transverse inserted between the master cylinder and the counter   cylinder, two balls (15) and (16) for locking and unlocking the module controlled by the axial movement of the striker (7) and a functional locking and unlocking ball (17) for the module preventing or authorizing its   operation by the action of the selector (23).   22. - Igniter plug according to claim 21, characterized in that the transverse detection ball (14) of the impact detector module is made of a dense material of the tungsten type. 23. - igniter plug according to claim 22, comprising a ring (34a) connected to a pin (34) locking a spoon (22) and an upstream striker (29) controlling the firing of the upstream part (3) of the chain, characterized in that it comprises, in the selector safety position (23), means   prohibiting the extraction of the pin (34). 2721394   24. - Igniter plug according to claim 23, characterized in that the means preventing the extraction of the pin (34), in the safety position of the selector, consist of a circular rib (26e) of the case (26) and an elastic lock (23a) of the selector, trapping part of the ring (34a).   25. - Igniter plug according to claim 24, characterized in that the rotary selector (23) occupies an initial safety position and takes, by successive rotations of 90, at least three different positions, each corresponding to one of the modes of operation: - in the safety position, the pin (34) is locked, the pyrotechnic train is interrupted by the element (27) maintained in the radial position, the striker (7), the three pins of which (7e) are opposite the three short safety lights (20a), is locked by the ball (8) engaged in the internal circular groove (7f) of the striker, the toothed wheel (18) of the timer module is located away from the racks (7c) of the striker, and the impact detector module is locked by   the two balls (15) and (16) respectively blocking the master   cylinder (10) and the counter-cylinder (12) under the action of the striker (7) in the initial position, in addition the functional locking ball (17) held by the selector (23) also blocks the master cylinder (10 ), - a first rotation of 90 of the selector, corresponding to the fusing operation of the load, causing successively, the unlocking of the pin (34) authorizing its extraction, the alignment of the pyrotechnic train by rotation of 90 of the element interruption (27), and the relative rotation of the striker (7) relative to the neutralization module (20) by bringing the three lugs (7e) of the striker opposite the three longer lights (20b) of the module corresponding to the position of functional neutralization of the striker, the timer and impact detector modules remaining inactive, - a second rotation of 90 of the selector, corresponding to impactful operation, causing moreover, the release of the function locking ball nel (17) of the impact detector module, the latter being housed in an internal circular groove (23b) of the selector to make this module active, 26 2721394   - A third rotation of 90 of the selector, corresponding to the striking-fusing operation, causing moreover, the alignment of the toothed wheel (18) of the timer module with the first rack (7c) of the striker corresponding to a percussion delay of one second, the impact detector module remaining active.   26. - Igniter plug according to claim 25, characterized in that, the selector (23) being in the striking-fusing position, three successive additional rotations in the same direction of the selector, causing the alignment of the toothed wheel (18) of the timer module with respectively, the second rack (7c2) of the striker corresponding to a percussion delay of seven tenths, the third rack (7c3) of the striker corresponding to a percussion delay of four tenths and the fourth rack (7c4) of the corresponding striker to a percussion delay of one tenth of a second. 27. - Igniter plug according to any one of   Claims 21 to 26, characterized in that, in position   striking and striking fuse of the selector (23) and in the absence of operation of the impact detector module, the module   self-destruction (5a, 5b, 5c, 7d) associated with the control means (5, 6) of the striker cause the ignition of the downstream part (4) of the chain followed by the explosion of the machine.